1. Field of the Invention
This invention relates to a method of reconstructing an image from compression-processed image signals. This invention particularly relates to a method of reconstructing an image from compression-processed image signals wherein deterioration in the image quality of a reproduced image caused by signal compression is minimized.
2. Description of the Prior Art
Image signals representing half tone images, such as television signals, are composed of enormous amounts of information, and a broad-band transmission line is required for transmission of the image signals. Such image signals involve much redundancy, and various attempts have been made to compress the image signals by restricting the redundancy. Also, in recent years, recording of half tone images on optical disks, magnetic disks, or the like has been generally put into practice. In this case, image signal compression is generally conducted for the purpose of efficiently recording image signals on a recording medium.
One of the methods of image signal compression that has been widely applied is an irreversible compression encoding method such as orthogonal transformation or prediction encoding.
With the aforesaid irreversible compression encoding method, image signals can be compressed reliably. However, when such signal compression processing is carried out, there is some loss of image signal. Though the irreversible compression encoding processing is devised so that the image signals that are lost are those that are not so important for image reconstruction, deterioration of the image quality of the reconstructed image is inevitably caused by the loss of the image signal in the case where, for example, the signal compression ratio is increased markedly.